This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.
Guide pins, also called locator pins, are used in various tooling applications to provide precise alignment or placement of certain parts prior to performing subsequent manufacturing processes. Processes where such locator pins are used to align various parts prior to subsequent processing include, but are not limited to, welding, aligning stacked or mating panels, and chases. The function of these pins is to align the parts consistently using reference holes or datum points.
Because of this repetitive insertion and removal, the pins are required to have adequate wear resistance for repeated motion against friction during the alignment process, and adequate corrosion resistance due to interactions with chemicals or vapors with which the pins can come into contact in the fabrication process. As these locator pins are used in aligning parts, for example, before resistance welding in applications like vehicle body fabrication, high wear resistance of these pins reduces the equipment downtime required for replacement of the pins and hence can result in lower operating costs.
Wear resistance is usually correlated to hardness of the coating. Pins used for aligning parts in the welding application also need to have high electrical insulation property in order to maximize the electrical current through the welding electrodes. During the welding process small particles of weld material are expelled from the welding operation called weld spatter that often adhere to the objects close to the welding area. Weld spatters on locator pins are undesirable as weld splatters make subsequent removal and insertion of the pins difficult. Low surface roughness of the pins is desirable as it allows for improved wear characteristics as well as easy alignment of the parts for welding.
While uncoated locator pins made of metals or alloys have the dimensional stability they lack adequate wear resistance and corrosion resistance properties required.
Thus a great need exists to produce locator pins, especially those containing a metallic core (such as aluminum or steel) with high wear resistance, high corrosion resistance, and low surface roughness. In addition, there is need for the locator pins to be electrically insulating. Further, it is highly desired to produce the ceramic coating by utilizing environmentally friendly processes with no hazardous by products whenever possible.